Oh, and reeseisthatbeast has made an omake for chapter 13. It is at the end of that chapter, if you wish to read it.

Checklist 15: Don't Starve. Hungry Workers Work Less Efficiently.

Three hours later after conclusion of the First Order...

Shirou collected his tray. Shepherd's pie today. Judging by the scent, it looked like they had added a secret ingredient. Shirou couldn't wait to try and figure out what ingredients they had changed or added. When he would meet Saber again, she might appreciate a good meal from her homeland. For nostalgia's sake.

Shirou turned around and stopped as he saw Lyudmilla Baran behind him. Shirou quickly stepped to the side to get out of her way. She was probably hungry and wanted a meal.

"Sorry," she said quietly.

"What was that?" Shirou asked, not able to make out what she had said.

"Sorry for accusing you," she said again, at the same volume. "You were used against your will. You didn't mean to. You were just another's tool."

"I'm sorry, I still can't hear you," Shirou repeated, leaning forward to hear her better. "Can you say that again?"

"That's all," she said at a slightly louder than normal volume before turning around, her shoulder length black hair flying up from how fast she spun. Then she hurried away, looking like she had someplace to be.

Shirou blinked after her. Then shrugged.

He didn't know what she had asked for and he had let her know that he couldn't hear her. If she was satisfied with what she had said, then obviously it wasn't meant for him to hear. She obviously hadn't been asking for his help else she would have repeated it loud enough for him to hear.

Besides, he had Shepherd's pie to eat! Which fortunately enough had not been stolen from any actual shepherds. Shirou would hate to eat another's lunch.

Today was a good day, Shirou reflected as he walked over to a cafeteria table. His eyes met Hooke who had been eating her own meal. She sniffed disdainfully and turned away.

Shirou noted that she was sitting alone, several tables away from anyone else. She didn't look like she got along with anyone and didn't want to.

But then again, most of the magi had died a few days ago so any friends she had were probably dead.

Shirou sat down at an empty table, mind reflecting on the recent hours.

After Caster had finished fixing the Fire of Prometheus about an hour ago, she had arrived at the Rayshift room and had spent a few minutes examining Shirou for any conditioning or mental interference left over. After clearing the spells out and releasing his suppressed memories that Lev had hidden from Shirou, Leonardo had given him a clean bill of health and proclaimed him free and independent if out of Od.

Shirou was no longer under an enemy's control. Not only that, he had saved someone from dying and life was good.

For him at least. Not so for everyone else who had died in Lev's treachery. Shirou's small smile faded at the reminder of everyone who had died.

He hadn't managed to save everyone. Maybe if he had been better at resisting mental magecraft, he could have discovered Lev's efforts before the bomb went off.

But then again, Leonardo had determined that if Shirou's Origin didn't leave him with an innate vulnerability to being taken control of, Lev probably wouldn't have tried. After all, Lev Lainur had chosen Shirou over someone who didn't have circuits and wouldn't have been able to resist at all.

As far as Leonardo could tell, he had chosen Shirou partly to have someone who could move around freely as they got closer to the exact date and partly to ensure that Shirou was down there when the bomb went off. One of the compulsions placed on Shirou had been to be near the power generator that day. If it hadn't been for that compulsion, Shirou might have been somewhere else, like say double checking lights somewhere else in Chaldea like he originally planned to be doing.

Shirou had been chosen as a tool in order to be discarded.

It was only his open circuits and reflex to manifest blades throughout his body that had saved him from dying by the very bomb he had planted. The shrapnel and explosion had deflected off the blades at the edges of his skull and ribs rather than cut through like it had to everyone else. The blades had been problematic but once inside the Bounded Fields of the infirmary and the blades removed, he had been able to recover.

Once again, he had survived. Once again, he alone had made it through something that had killed everyone.

He hated it about as much as he hated the Fuyuki Fire. However, the past was done and he was alive. The only thing he could do was learn from it, mourn the past, save what he could, and move on. And what he could do now was take a seat, eat lunch and discover what ingredients had been used.

"Oooooh," Roman sighed in relief he slid down into the seat opposite Shirou, his own shepherd's pie on his tray. The long-haired man smiled at Shirou in greeting. "I'm famished! How are you doing, Shirou?"

"I'm alright," Shirou said simply. A now removed compulsion to commit suicide wasn't worth mentioning. "Caster cleared me of the lingering mental magecraft so I'm my own person now. Also, Lev only used me to plant the bombs in his pre-selected locations. Caster thought that he might have been too busy to plant them without someone noticing after the date and time for the Rayshift had been chosen so he prepared the timer for the bombs himself but gave them to me to put into place."

Shirou had only placed two of the three bombs. Lev had placed the bomb in the control room himself and provided the bombs and prepared the places for the bombs. All in all, Shirou had just been someone else's tool for the attack.

Shirou clenched his fist that wasn't holding his fork.

That was wrong. It was just morally wrong.

Roman listened, taking his first bite while Shirou had spoken. Swallowing, the acting director said. "Well, at least that is resolved."

Shirou shook his head in disagreement. "It isn't resolved until we know how Lev either was possessed or turned and who is behind him. If they could do it to Lev, they could do it to someone else as well."

"Well, yeah," Roman agreed somewhat uncomfortably. "But that isn't our function. We just need to reestablish communication with the UN and Clock Tower and get whichever of CHALDEAS, LAPLACE, SHEBA, or TRIMEGISTUS is malfunctioning to work again. They can take care of Lev and his allies."

"One of them is malfunctioning?" Shirou asked, taking a bite.

Those were four of the big five inventions of Chaldea. The ones that Chaldea was operating on for the First Order. CHALDEAS for providing information about the present, past and future. LAPLACE, SHEBA and TRIMEGISTUS were all based around analyzing CHALDEAS as well as taking care of other minor functions.

If one of them was sabotaged or malfunctioning, then they had been lucky to get the Masters back alive.

"Yeah, they keep on saying that there isn't anything to detect. No human anywhere in the past 2000 years or even over the next year or two, much less for the next century. But of course, that is impossible." Roman shook his hand.

"Yeah, we are here. It should be able to detect us at the very least." Shirou agreed before taking a bite. "Do you need any help?"

"Yeah, but that is mostly down in the generator room," Roman said. "We have most of the magi looking over the four but they wouldn't know even half of the parts for a generator if it was labeled. Thanks for offering though."

"It's nothing," Shirou said. He not only didn't like being bored, especially when there was something he could be doing, but he wanted to help. "More for my own benefit really."

"Benefit- ah," Roman grimaced at the thought. "You know Shirou, it wasn't your fault. Just because someone overpowered you doesn't mean that you are responsible for what they did to you afterwards. You did your best, I am sure but sometimes life is just unfair like that."

"Ah," Shirou noncommittedly added. He really didn't want to talk about it.

Shirou looked down at his plate. He had been so happy over saving Olga and now this.

Olga.

"Come to think of it," Shirou brought his eyes up now that he remembered something they would need to worry about. "How are we going to feed Olga?"

"Just manifest the Reality Marble," Roman said dismissively as he continued eating. "Have food ready to be given to her. Should be simple enough."

"But I don't know how," Shirou admitted. "I can pull things from it easily enough but I don't know how to manifest it outside my body."

"It just requires that you connect a personal Bounded Field to the Reality Marble and have a picnic basket of food or something in the field. Keep it up long enough for her to eat it. It is not rocket science," Roman said easily before taking another bite. "Oh, and if you are worried about the food staying inside of her, it doesn't work that way. Once she has ingested the food or drink, ending the Bounded Field shouldn't take it out of her stomach or anything."

"About that-" Shirou sheepishly started.

Roman groaned and covered his eyes with one hand. "Why do I have the feeling I won't like the sound of this?"

"-I don't know how to make a Bounded Field correctly. Manifesting my Reality Marble inside a Bounded Field is literally the last step I have to completing it," Shirou finished, feeling somewhat embarrassed. "I think I can figure out how to flip between my Reality Marble and the world sooner or later, but I don't know how to limit it to a smaller area. Without limiting the size, I'd spend all my Od in just the first second and have it collapse the next."

Roman stared at Shirou, his next bite forgotten on his fork that was laying on his plate.

"How do you not know how to make a Bounded Field?!" Roman asked in shocked disbelief. "It's one of the basics of magecraft, isn't it? Or did that change while I wasn't paying attention?"

"Yeah, it still is," Shirou agreed. "But I'm rubbish at magecraft and my first teacher wasn't able to teach me much. My second teacher tried once but after I messed it up badly enough to badly damage her workshop, she postponed that lesson. We haven't gotten back to it."

Rin was planning on completing that lesson the next time I visited the Clock Tower, Shirou remembered. Hopefully, she wouldn't mind him studying ahead.

Who was he kidding. She would be extremely upset at these circumstances. Good thing he put in a good word for her to be a Master at Chaldea? Maybe it would keep her from killing him via Gandr sickness.

Roman groaned and hung his head, bringing both of his elbows onto the table while face palming.

"One of the most basic techniques of magecraft and the strongest expression of a Reality Marble and you don't know how to do it," his muffled voice said from beneath his hand covering his face.

"Sorry," Shirou apologized.

He just hadn't prioritized learning how to make a Bounded Field after his first mess up. He had chosen to learn other things like about the Reverse Side of the World and Avalon.

"Well, this isn't good, not good at all. But I guess that is the hand we are dealt," Roman sighed as he uncovered his face. "How about we have Da Vinci teach you? Shouldn't take long, she is pretty talented at everything so teaching should be on the list too."

"Sounds good," Shirou agreed. He would have to be a fool to not accept lessons in magecraft from a Caster Servant. Especially when someone's life was on the line. Belatedly, he remembered something he should warn Roman about. "Oh, but due to my alignment of Element and Origin, it might take me a lot longer than normal to learn it."

Roman frowned and closed his eyes, looking for all the world like he was dreading an oncoming headache that he couldn't avoid. "How much longer?"

"I don't know," Shirou said honestly. "It seems to be either multiplicative or exponential. What could take a genius a day could take me a week or two, possibly three, to learn."

Roman slammed his hands down on the table as he opened his eyes and yelled. "That makes things worse! We don't have weeks, barely even days! She'll die long before then!"

Shirou let the doctor ramble on and run the fear out of the poor man's system while taking bites from his pie. Some stress relief such as venting helped people and Roman was probably the most stressed of them all.

The lamb was especially good. Perhaps they had prepared it in a specific manner?

The doctor eventually noticed everyone else staring at him and abruptly sat back down, squawking an apology. A few relaxing breaths later, he opened his eyes, ready to continue.

"Alright, so no chance of time moving slower in there? Or being outside of time?" the doctor sighed before asking without any hint of hope in his voice. More of a resigned acceptance to the inevitable.

"Let me check. Nope, hasn't changed since the last time you asked," Shirou answered with a bit of sarcasm.

"Right, right. No need to be so mocking," the doctor continued, closing his eyes to better concentrate. "How long do you think she can live in there?"

"There isn't any food or water so three days, I think," Shirou replied seriously before hesitating. "Could we not insert food or drink directly into the Reality Marble? Like how we did Olga?"

"No," Roman instantly rejected as he pulled out his comm and started looking through some documents and files. "We need some resistance to magic. Too much like if Olga had resisted it and we would end up with her not being able to enter and getting stuck outside. Too little, like if it was food with almost no resistance to magic, then it will slide right past and end up somewhere else. We could try to enchant it but I don't know what trying to put dead organics into a Reality Marble would require. To find out would require setting up new experiments, which requires time, which Olga does not have. No, the only way is to put up a Bounded Field and use that area to enter directly into the Reality Marble. And as a magus she should be able to last a bit longer than three days but the Singularity has already drained her Od and resources. So let's get this done by the third day or else we might lose her anyways."

"I see," Shirou said, frowning. The doctor's logic made sense.

But now it was a race against time to see if Shirou could learn how to use a Bounded Field efficiently enough for them to give Olga time to eat.

While Shirou was a third-rate magus and had been for over a decade, learning new forms of magecraft was not his forte.

"We better contact Da Vinci," Roman said, worriedly, reaching out to his communicator on his wrist. "There isn't any time to waste."

Shirou nodded and hurried to finish his food.

He'd need the energy for the lessons.

"Okay, first thing we need to do is streamline everything," Caster said as she typed away at a virtual keyboard, her eyes firmly locked onto a separate hologram of text and numbers. "By that, I mean everything. Your diet, your sleep cycle, your work schedule and your medicinal intake. Since this is a long-term learning effort with a short-term need for results, your sleep is extremely important. Without proper sleep spread out at important moments, you'll take longer to learn the next step than we can afford. I've already sent you the documents containing what foods you'll need to eat and what recreational materials would enhance your learning in addition to everything else."

"Um," Shirou began as he realized just how busy the Servant was. She was multi-tasking on three different things already and was about to supervise his teaching. Would she be able to do all of that?

Also, just how controlling would she be? Sleep? Diet? Exercise? Medicinal intake? What next? When he pees and how long?

"Do—"

"The first thing we need is for an analysis of what you already know. See what you already know, what progress you have, and what you are doing wrong," Leonardo interrupted as she shifted to have a better view of Shirou. "Just create a small cube bounded field in front of you right now. Small, since maintaining your reserves and reducing the strain on your circuits is important. Ignore what you don't know, I need to see what steps you do know and how well. Begin."

"Wait, wait!" Shirou protested. "First up, do we have to redesign everything about my life?"

"Well, no," Leonardo admitted as she continued her work. "But if we control when I'm working with you, I can teach you while doing this" she nodded to the work beneath her "and everything else I have to get done. If I'm lucky and nobody else sets off a bomb, I can get back to my personal projects by the end of the week. My parrot was in the middle of an upgrade and I would like to finish it."

"Oh," Shirou realized. This was just scheduling. Taken to the extreme that not even Rin or any of her classmates at the Clock Tower would do. "Wait? Did you say you were upgrading a parrot?"

"He's beautiful!" Da Vinci gushed. "Using the better precision on Archimedes principle, plus a few motors, I can get him to require 1.8% less magical energy to fly 1.34 times longer all the while including new colors of feathers! Now make me a Bounded Field."

"And this will help us save Olga faster right?" Shirou asked.

"Yes," Da Vinci said resolutely. "If a slowpoke doesn't waste my time by asking redundant questions."

"All right," Shirou said, still uncertain about how this would work. But if it would help, and time was short… "Trace on."

The Servant's eye twitched.

"Nerve circuits," she said disgustedly even as she continued her work. "Why did you even— Never mind. You aren't using them now."

"How did you know I once used nerve circuits?" Shirou asked curiously as his circuits throbbed in anticipation of being used.

"I'm the universal genius, Leonardo da Vinci," she said like it was as obvious as the sun in the sky. "Your body slightly tensed up like it was expecting physical pain. A proper circuit would only be spiritual pain but you had a physiological pain expectation focused on the spinal cord. However, your passive spiritual energy output is too large for a nerve circuit so you must have been using proper circuits. The only reasonable explanation is that you spent years training your body to use nerve circuits, only to switch over to proper circuits. If you had a crest, it could be possible for you to be using that instead, but you do not so that option was disregarded."

Shirou blinked at the accurate run-down from very slight clues.

"Um, yeah," he admitted. "Pretty amazing you got all that though."

"I am a genius," Leonardo puffed herself up with a proud smile. "Really, you should expect stuff like that from me, the artist of the Mona Lisa. A simple analysis like that is nothing compared to recreating the Mona Lisa. My body is a work of art, isn't it?"

The Caster twirled around, dress fluttering as she showed off her body.

"Uh," Shirou blinked at the rapid change in topic before asking in a bit of confusion "You created your body?"

Were all Caster Servants capable of doing stuff like that?

"Of course," Leonardo said. "Modeled it off of the perfect beauty. Wouldn't you if you could? Come on, surely my body is worth more than a few passing praises?"

"Sure?" Shirou asked, getting lost in Leonardo Da Vinci's tempo.

Why was she bouncing around from topic to topic so fast?

"It is beautiful," Shirou agreed, figuring that the Servant was fishing for compliments. "Couldn't tell that it was artificial at all."

"What would be the point of inhabiting an inhuman or ugly body?" Leonardo asked, looking at him like he was crazy before sighing. "You don't even see the mathematical ratios, did you?"

"Nope," Shirou admitted without shame. He had done okay in math class, but that was a decade ago.

"Must do your sword-crafting by instinct then," Da Vinci analyzed with a remote look in her eyes. "Except, you throw some borrowed experience at it and then act by instinct, relying on your Sword Origin to accomplish feats in your specialty that most swordsmiths wouldn't be able to even imagine. Well, I'll have to adjust the lesson plan for that mindset then. An experience-focused and intuitive mindset, not discerning of whose experience."

"Ah, right," Shirou shook his head to refocus on the purpose for them being here. Saving Olga by learning how to craft Bounded Fields.

"Now, time is short so let's get started." Da Vinci said before returning to work. "Chop, chop."

Olga had unbuttoned the collar of her shirt and had taken off her jacket for use as a cushion.

This Reality Marble was too hot! The sun shone down and baked her and there wasn't even a tree or building she could use for shade! The only things around that could offer shade was the big rock sword at her back and it was just as hot as everything else!

At least she had managed to tilt it over so that it actually gave shade now. Why did Shirou's Reality Marble have the sun straight overhead? Didn't he consider how it would feel to be inside it?

And why was everything so plain! The ground was rocky, cracked, and barren with naught but a distant mirage of green and a low hill and ridges. When she had been thirsty, she had walked towards the green image, hoping to find some water but it had never gotten any closer.

And then she had realized that the Reality Marble was a loop. She had passed the exact same sword and hill three times before she was convinced. The green mirage was not actually part of the world, just a distant illusion of life and water. It seemed that there was nothing that could live here and nothing did.

Honestly, with all the swords sticking straight up, not a single one on its side, it looked like a giant graveyard.

It was creepy. Like you could throw a ghost or poltergeist into here and it would not feel out of place at all!

Olga scowled while the sun continued shining. She was the ghost. She didn't want to be here at all!

Olga's stomach growled and she glared down at it before giving up. There was nothing to eat, nothing to drink and it was just too hot!

Honestly, there was nothing to do here. She couldn't work, she couldn't find food, her throat was parched and sore, CHALDEAS needed maintenance, her only friend had betrayed her, and she was stuck in this miserable excuse for a Reality Marble!

She sniffed as her nose still felt runny after her cry.

When were they going to get her out of here!?

Note that Shirou isn't leaching off of Archer's experience. He doesn't have the cheat to use Archer's experience to skip over the obstacles. He knows that his tracing is focused on his Reality Marble but not how to switch reality with his own marble. And even if he did know how, he would need a lot more energy than he has to do what UBW route Shirou did.